1. Field of the Invention
The field of the invention comprises devices generally known as vacuum support cups.
2. Description of the Prior Art
Heretofore various constructions have been proposed for vacuum cups of the type which are attached to an object for lifting of that object. Vacuum cups are used, for example, for attachment to plate glass from a supporting or lifting device. A known prior art vacuum cup construction comprises a solid rubber cup with a central vacuum port which permits a vacuum to be drawn within the cup. Another embodiment comprises a solid rubber cup laminated to a metal backing. A third embodiment employs two metal plates which clamp upon a preformed solid rubber sealing ring to form a cup upon which a vacuum may be drawn. A fourth embodiment comprises a structure similar to the third embodiment that has been modified by laminating a soft rubber ring to the edge of the solid rubber cup. Yet another embodiment in the prior art comprises a single metal plate with a soft rubber ring laminated to the base of the metal plate for purposes of supplying a vacuum seal. In all instances, a cup is formed with a flexible edge to engage an object and a vacuum port is connected to the inside of the cup whereby the cup may be evacuated to effect attachment of the cup to an object. There as remained, however, the need for an improved vacuum cup construction.